Whitened coffee concentrate

ABSTRACT

A stable, whitened coffee concentrate that is a mixture of milk solids, soluble coffee solids, and coffee aroma, that has a solids concentration above about 25% by weight and a process for making the concentrate. The coffee aroma stabilizes the concentrate.

FIELD OF THE INVENTION

The invention relates to a stable, whitened coffee concentrate and aprocess for producing the concentrate. The invention also relates to amethod for stabilizing whitened coffee concentrates.

BACKGROUND

Coffee products that contain mixtures of soluble coffee solids and milksolids are commonly found in two forms; as soluble beverage powders oras ready-to-drink liquid beverages. Although these products appear to besimple, numerous difficulties need to be overcome in order to producethem. For example, the inherent instability of coffee and milk mixturescreates a significant problem that needs to be overcome.

For soluble beverage powders, a common problem is the appearance offlocculated milk proteins when the beverage is reconstituted with water.The flocculated milk proteins negatively affect consumer acceptability.The problem of flocculation of the milk proteins in coffee beverages hasbeen satisfactorily dealt with by a process in which the milk proteinsare subjected to a processing step that controls flocculation. Afterprocessing in this way, any flocculated milk proteins in thereconstituted beverage are too small to be visible. This process isdescribed in U.S. Pat. No. 5,620,733.

For ready-to-drink liquid beverages, in addition to the problems withflocculation of milk proteins, it is found that lipids in the beveragerise to the surface of the beverage in the form of globules. Theseglobules form an agglomerated, white layer known as a cream layer andthe phenomenon is known as creaming. Upon shaking of the container, theglobules usually re-disperse within the beverage, however, a persistent,visible white ring usually remains on the container at the interfacebetween the liquid beverage and the gas above it. The presence of thisring is unacceptable to consumers. Processing techniques and stabilizersare necessary to deal with the problem.

The stability problems become even more pronounced when whitened coffeeproducts are formulated into a liquid concentrate. Typically, the coffeecomponent of these concentrates develops increased acidity over time.The increased acidity negatively influences the taste of productsreconstituted from the concentrate. Furthermore, the increase in acidityleads to other problems such as curdling of the milk component,gelation, and sedimentation. Therefore, despite the advantages offeredby whitened coffee concentrates they are not commercially available,since the consuming public will not accept products that exhibit theabove-identified problems. Thus, there is a need for a stable, whitenedcoffee concentrate that avoids the above-identified problems.

SUMMARY OF THE INVENTION

The present invention relates to a stable, whitened coffee concentrate;a method for stabilizing a whitened coffee concentrate; and a method formaking the stable, whitened coffee concentrate. The stable, whitenedcoffee concentrate includes concentrated milk components, concentratedsoluble coffee solids, and coffee aroma, wherein the solidsconcentration of the whitened coffee concentrate is above about 25% byweight. The ratio, on a dry basis, of non-fat milk solids to coffeesolids may be between about 1:0.1 and 1:0.7. The concentrate showssubstantially no change in viscosity after at least 5 months storage atroom temperature.

The coffee aroma may provided in the form of an aromatized coffeeconcentrate. Preferably, the aromatized coffee concentrate has a totalorganic content (TOC) of above about 300 mg/100 g of aromatized coffeeconcentrate and more preferably a TOC of above about 450 mg/100 g ofaromatized coffee concentrate. Preferably, the coffee aroma alsoincludes highly volatile aroma components.

The concentrate may include between about 50% and 60% sugar, betweenabout 15% and 25% non fat milk solids, between about 8% and 15% solublecoffee solids, and between about 8% and 15% milk fat, the percentagesbeing on the basis of dry weight. Preferably, the solids concentrationis between about 70% and 80% by weight. Preferably, the concentratedsoluble coffee solids are enzymatically hydrolyzed. The concentrate mayalso include one or more additives such as buffers, sweeteners,flavorings, colorings, emulsifiers or mixtures thereof. The concentratemay be packaged in a single-serve sachet.

The method of stabilizing the whitened coffee concentrate involvesadding to a whitened coffee concentrate a sufficient amount of coffeearoma to stabilize the coffee concentrate and provide a stable, whitenedcoffee concentrate having a solids concentration above about 25% byweight,. Preferably, the amount of coffee aroma is between about 1 and 3percent by weight and contains highly volatile aroma components.

The stable, whitened coffee concentrate is prepared by combiningconcentrated coffee solids with concentrated milk components to providea whitened coffee concentrate; adding to the whitened coffee concentratea sufficient amount of coffee aroma to stabilize the whitened coffeeconcentrate and provide a stable, whitened coffee concentrate having asolids content of above about 25% by weight; homogenizing the stable,whitened coffee concentrate to increase the dispersion of fat in thestable, whitened coffee concentrate; and packaging the homogenizedstable whitened coffee concentrate. The amount of coffee aroma may bebetween about 1 and 3 percent by weight. Preferably, the coffee aromacontains highly volatile aroma components. In addition, one or moreadditives such as buffers, sweeteners, flavorings, colorings,emulsifiers or mixtures thereof may be added to the stable, whitenedcoffee concentrate. The whitened coffee concentrate may be subjected tocolloidal milling.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The invention provides a stable, whitened coffee concentrate that can bestored under shelf conditions for long periods of time withoutsignificant stability and flavor-degradation problems. For example, theconcentrate may be stored for more than about 5 months, preferably morethan about 9 months, and more preferably more than about 12 monthswithout significant stability and flavor-degradation problems. Thestable, whitened coffee concentrate does not exhibit a harsh acidityafter storage and exhibits a reduced tendency to undergo gelation andsedimentation during storage. By gelation is meant an increase inviscosity of the concentrate over time. By sedimentation is meant theformation of a solid that precipitates from the concentrate and settlesto the bottom of the container in which the concentrate is packaged.

The whitened coffee concentrate comprises a mixture of concentrated milkcomponents, concentrated soluble coffee solids, and a stabilizing amountof a coffee aroma. The whitened coffee concentrate has a solidsconcentration above about 25 percent by weight, preferably between about30 and 75 percent and more preferably between about 55 and 72 percent.

The concentrated soluble coffee solids may be provided in the form of asoluble powder or suitable base coffee concentrate. By coffeeconcentrate is meant a concentrated extract of roast coffee. The basecoffee concentrate may be prepared, by one of two methods. In the firstmethod, soluble coffee powder is dissolved in water to provide a baseconcentrate with the desired concentration of coffee solids. In thesecond method, a coffee extract is obtained by a coffee extractionprocess and the resulting extract is concentrated to the desiredconcentration of coffee solids. The coffee extract may be obtained byextracting roasted coffee beans with a solvent. Methods for extractingroasted coffee beans and for concentrating the resulting extract arewell known to those of ordinary skill in the art. Any suitableextraction procedure or concentration procedure may be used. The choiceand design of the extraction procedure and concentration procedure is amatter of preference and has no critical impact on the invention.

Optionally, the concentrated coffee solids may be subjected to enzymatichydrolysis; for example using a gamanase. Hydrolysis using a gamanaseoffers the advantage of increased stability and a further reduction insedimentation.

The concentrated milk components may be provided in the form of apowdered milk or a suitable milk concentrate. The milk concentrate maybe prepared by any means available to those of ordinary skill in theart. For example, the milk concentrate may be prepared by the procedurecommonly used to produced condensed milk. Alternatively, the milkconcentrate may be prepared by concentrating milk, for example, byevaporation. The solution of milk concentrate, having the selectedsolids content, may also be prepared by combining skimmed milk solids,milk fat, and sugar with water. Optionally, additional milk proteinsources such as whey or casein may be added. If a milk concentrate isused, the milk concentrate preferably has a milk solids content aboveabout 30% by weight. Preferably, the milk concentrate has a solidsconcentration of between about 50% by weight and 85% by weight. Thefinal product, i.e., the whitened coffee concentrate, preferably hasbetween about 15 percent and 25 percent of skimmed milk powder andbetween about 5 percent and 15 percent of milk fat.

Coffee aroma are the volatile components of coffee that produce thecharacteristic fragrance of coffee. The coffee aroma is convenientlyprovided in the form of a highly aromatized coffee concentrate. Thearomatized coffee concentrate is prepared by adding coffee aroma to acoffee concentrate. Methods of preparing coffee concentrates are wellknown to those of ordinary skill in the art. The coffee aroma is in theform of natural coffee aroma components that are collected during thepreparation of soluble coffee powder. This may be done by standardprocedures for collecting coffee aroma components or by suitablymodifying the standard procedures.

Preferably, the natural coffee aroma includes highly volatile aromacomponents. Highly volatile aroma components are those which condense ata temperature below about 0° C. To recover highly volatile aromacomponents, the standard procedure usually entails flushing volatilearoma components from the coffee during processing using an inertcarrier gas such as nitrogen. The aroma-laden carrier gas is thenchilled to temperatures lower than about −40° C., and sometimes as lowas about −195° C., to cause the aroma components to condense. Thecondensed aroma components are then collected. Suitable procedures forcapturing coffee aroma are disclosed in, for example, U.S. Pat. Nos.3,823,241, 5,030,473, and 5,222,364, the disclosures of which areexpressly incorporated herein by reference.

Sufficient coffee aroma is added to the coffee concentrate to provide atotal organic concentration (TOC) of above about 300 mg/100 g ofaromatized concentrate. Preferably, the aromatized concentrate has a TOCabove about 350 mg/100 g, and more preferably above about 450 mg/100 gof aromatized concentrate. The aromatized coffee concentrate preferablyhas a solids concentration of between about 35 and 75 percent by weight,more preferably between about 35 and 45 percent by weight. Preferably,the coffee aroma is added in an amount of between about 1 and 3 percentby weight of the whitened coffee concentrate.

Unexpectedly, the coffee aroma stabilizes the whitened coffeeconcentrate. It is surprising that coffee aroma stabilizes the whitenedcoffee concentrate since coffee aroma is ordinarily more unstable thaneither milk concentrate or coffee concentrate.

The stable, whitened coffee concentrate may be produced from theconcentrated milk components, concentrated coffee components, and coffeearoma in several ways. The ingredients may be combined in an order. Forexample, the concentrated coffee components and the coffee aroma may becombined to form a mixture and the concentrated milk components thenadded to the mixture as a powder. Alternatively, the mixture may beadded to the concentrated milk components in the form of a milkconcentrate. As a further alternative, the concentrated milk components,concentrated coffee components, and coffee aroma are combined togetherin one step. Suitable mixers may be used to combine the ingredients.

The ratio, on a dry basis, of milk solids to coffee solids in thewhitened coffee concentrate of the invention is typically less thanabout 1:0.7, preferably between about 1:0.2 and 1:0.6.

Additional ingredients may also be incorporated into the whitened coffeeconcentrate as desired. Examples of additional ingredients include, butare not limited to, buffers such as sodium and potassium bicarbonate,di-sodium and di-potassium phosphate, sodium and potassium citrates, andvarious combinations of these buffers; suitable sweeteners such asmaltodextrin, saccharin, cyclamates, acetosulfame, sucralose, L-aspartylbased sweeteners such as aspartame, and mixtures of these sweeteners;suitable flavors such as vanilla, bourbon, whisky, chocolate, and thelike; artificial or natural colorings; suitable emulsifiers such asmono- and di-esters of glycerol and a fatty acid, glycerolmonostearates, sorbitol monostearates, esters or carbocyclic acids withmono-and di-glycerides, monosodium phosphate derivatives of mono- anddi-glycerides, lecithin, diacetyl tartaric acid esters ofmono-diglycerides (data esters), sorbitan esters, diacetyl tartaricacids esters of mono- and di-glycerides, succinylated mono- anddiglycerides, acetylated mono-and di-glycerides, hydroxylated lecithin,propylene glycol mono- and di-esters of fatty acids, polyglycerol estersof fatty acids, lactylic esters of fatty acids, and mixtures of theseemulsifiers.

The solids content of the whitened coffee concentrate is more than about25%. In one embodiment the whitened coffee concentrate has a solidsconcentration between about 65% and 85% by weight, preferably betweenabout 70% and 80% by weight. For example, the whitened coffeeconcentrate may have a solids concentration of between about 70% and 75%by weight. In another embodiment, the whitened coffee concentrate has asolids concentration of about 30% to about 35% by weight. If thewhitened coffee concentrate does not have the desired solidsconcentration, the desired concentration may be obtained by combiningthe whitened coffee concentrate with another concentrate having a higheror lower solids content, as required, to standardize the solidsconcentration of the whitened coffee concentrate to the desired value.

The water activity, a_(w), of the whitened coffee concentrate may bebetween about 0.80 and 0.95. The pH of the whitened coffee concentratemay be between about 5 and 8, preferably between about 6 and 7, and mostpreferably about 6.5.

After the ingredients are combined the whitened coffee concentrate mayoptionally be subjected to colloidal milling. Colloid milling reducesviscosity and sedimentation in the final product. Ordinarily, colloidalmilling is not necessary for whitened coffee concentrates having asolids concentration of less than about 50% by weight. Preferably thecolloidal milling occurs at elevated temperatures, for example frombetween about 100° C. and 150° C. The time for which the whitened coffeeconcentrate is subjected to colloidal milling may be selected asdesired, preferably the concentrate is subjected to colloidal millingfor a period of time between about 1 minute and 20 minutes.

If the whitened coffee concentrate is to be aseptically filled intocontainers, it is preferably heat treated at this stage of the processto sterilize the product. For example, the whitened coffee concentratemay be subjected to ultra high temperature (UHT) treatment at atemperature above about 115° C. Preferably the temperature is betweenabout 120° C. and 150° C., more preferably between about 120° C. and155° C. Typically, the mixture is held at the raised temperature forless than about 5 minutes, preferably for between about 1 and 5 minutes.Preferably, the mixture is held at the raised temperature for sufficienttime to provide a F₀ value of at least about 4.

Whether heat treated or not, the whitened coffee concentrate may then besubjected to homogenization to increase the dispersion of fat in thewhitened coffee and provide a more uniform product. Homogenization ispreferably carried out in two stages. For example, for whitened coffeeconcentrates that have been subjected to colloidal milling,homogenization may be carried out in a first stage at a pressure ofbetween about 5 Mpa and 25 MPa followed by a second stage at a pressureof between about 1 MPa and 5 MPa. For whitened coffee concentrates whichhave not been subjected to colloidal milling, homogenization may becarried out in a first stage at a pressure of between about 15 Mpa and30 MPa followed by a second stage at a pressure of between about 3 MPaand 10 Mpa. All processing steps are performed under conditions whereinloss of the coffee aroma from the whitened coffee concentrate isminimized.

The whitened coffee concentrate is then filled into suitable containers,with or without thermal treatment prior to filling. In one embodiment,the whitened coffee concentrate is heated to a temperature of betweenabout 80° C. and 100° C. for a period of less than about 1 minute andthen hot filled into suitable containers. In another embodiment, thewhitened coffee concentrate is aseptically filled into suitablecontainers. In another embodiment, the whitened coffee concentrate isfilled into suitable containers and then retorted. In yet anotherembodiment, the whitened coffee concentrate is frozen and then filledinto a suitable container.

Containers suitable for containing the whitened coffee concentrate ofthe invention can be flexible, semi-rigid or rigid depending upon theprocess conditions and the type of product desired. Suitable containersinclude, but are not limited to, stick packs; sachets; carton-based;tetrahedron packs (closeable or not); unifill packs; squeezeable plasticbottles; stand up pouches; plastic cups; and the like. The containersshould be such that they provide a barrier to minimize exposure of thewhitened coffee concentrate to water vapor, oxygen, and lighttransmission.. A sufficiently high barrier can be obtained, for example,with a container made of a film that containspolyester/aluminum/polyethylene layers.

In one embodiment the whitened coffee concentrate is packaged in singleserving containers. For single serving containers, the container issuitably a sachet or stick pack. By stick pack is meant a long, narrowsachet. Equipment and material for producing these containers arecommercially available. Vertical form fill and seal machines may beused. Conveniently, the sachet or stick pack has a tear off sectionwhich may be provided in the usual manner by a notch, fancy cut, orlaser cut. Presenting the whitened coffee concentrate in this formoffers the advantage that the whitened coffee concentrate may beprovided in a convenient, single serving pack. The consumer then needonly open the pack, pour or squeeze the concentrate into a cup, and addwater. Typically, the stick pack contains between about 20 g and 50 g ofthe concentrate.

Beverages produced from the whitened coffee concentrate have a goodaroma and flavor profile without harsh acidity. In addition, thewhitened coffee concentrate of the invention has good stability and maybe stored for extended periods at room temperature.

EXAMPLES

The invention is further defined by reference to the following examplesdescribing in detail the preparation of the stable, whitened coffeeconcentrate of the invention. The examples are representative, and theyshould not be construed to limit the scope of the invention in any way.

Example 1

A coffee aroma is collected from freshly ground coffee and cryogenicallycondensed as described in U.S. Pat. No. 5,222,364. In addition, anaqueous aroma distillate was obtained by steam stripping a coffeeextract in a conventional manner. The condensed aroma and the aqueousaroma distillate were then mixed into a coffee concentrate that had acoffee solids concentration of about 50% by weight. The resultingaromatised coffee concentrate has a solids concentration of about 39% byweight and a TOC of about 382 mg/100 g of coffee concentrate.

A base coffee concentrate was prepared by dissolving soluble coffeesolids in water. The base coffee concentrate had a solids concentrationof between about 25% and 30% by weight. The base coffee concentrate andthe aromatised coffee concentrate were then combined in a mixer in aweight ratio of 5:1. The resulting coffee concentrate had a solidsconcentration of between about 25% and 30% by weight.

A milk concentrate containing about 22% by dry weight of skimmed milksolids, about 12% by dry weight of butter fat, and about 66% by dryweight of sugar was then added to the coffee concentrate in a mixer toprovide a whitened coffee concentrate. The ratio of non-fat milk solidsto coffee solids in the whitened coffee concentrate was about 1:0.58. Asmall amount of disodium phosphate, about 0.4% by dry weight, wasincluded in the whitened coffee concentrate. The whitened coffeeconcentrate was standardized to a solids content of about 72% by weight,a water activity of about 0.83, and a pH of about 6.5.

The whitened coffee concentrate was then subjected to colloidal milling.The milled concentrate was then homogenised in two stages.Homogenization was carried out in the first stage at a pressure of about10 MPa followed by a second stage at a pressure of about 3 MPa. Thehomogenised concentrate was then heated to about 93° C. for about 45seconds by direct injection of steam. The hot concentrate was thenfilled into stick packs. Each stick pack containing about 20 g ofwhitened coffee concentrate. A vertical form fill and seal machine wasused to fill the stick packs. The stick packs were made from apolyester/aluminum/polyethylene film. The stick packs had a tear offsection provided by a laser cut.

The stick pack were opened and the contents squeezed into a cup. About150 ml of hot water was added and the mixture stirred. Reconstitutionwas instantaneous. A whitened coffee beverage was obtained. No milkflocculation was noticed and no lumps or other undissolved materialcould be detected. The beverage was tasted and found to have a smoothcoffee taste; no noticeable harshness or and acidity; and a welldefined, rich coffee aroma. The beverage had an excellent mouthfeel withno sandiness or dust-like texture.

Example 2

The process of example 1 was repeated except that no coffee aroma wasincorporated into the whitened coffee concentrate. The stick packs withno coffee aroma were labeled as group A. The stick packs of example 1were labeled as group 1. All stick packs were stored at 20° C. A samplefrom each group was opened after 1 month and each month thereafter for atotal storage time of 5 months. The viscosity and the sedimentation ofeach concentrate was determined. The results are provided in the TableI:

TABLE I Group Time (months) Viscosity (mPa/s) Sedimentation (mm) A 12800 0.4 2 3100 1.9 3 4800 2.9 4 5700 3.9 5 ND 7.0 1 1 2.000 0.4 2 16000.4 3 1800 1.9 4 2000 1.9 5 2000 1.9

The results indicate that the whitened coffee concentrate whichcontained the coffee aroma has superior stability. The viscosity of thewhitened coffee concentrate remained substantially constant indicatingthat the samples did not undergo gelation. Furthermore, sedimentationwas much less in the whitened coffee concentrate which contained thecoffee aroma.

Example 3

The process of example 1 was repeated except that base coffeeconcentrate was subjected to enzymatic hydrolysis using 1.5 L gamanaseprior to the addition of the coffee aroma. Stick packs containing thewhitened coffee concentrate were stored for a period of up to 9 months.After 1-3 months, stability problems such as creaming, coagulation,sedimentation, and gelation begin to reach unacceptable levels in thesamples of the whitened coffee concentrate that contained coffee solidsthat had not been hydrolysed with gamanase or did not contain coffeearoma. In contrast, the whitened coffee concentrate that containedcoffee solids that had been hydrolysed with gamanase did not showstability problems until after about 9 months.

The invention described and claimed herein is not to be limited in scopeby the specific embodiments herein disclosed, since these embodimentsare intended as illustrations of several aspects of the invention. Anyequivalent embodiments are intended to be within the scope of thisinvention. Indeed, various modifications of the invention in addition tothose shown and described herein will become apparent to those skilledin the art from the foregoing description. Such modifications are alsointended to fall within the scope of the appended claims.

What is claimed is:
 1. A stable, whitened coffee concentrate comprising concentrated milk components, concentrated soluble coffee solids, and added coffee aroma in an amount effective to stabilize the whitened coffee concentrate, wherein the solids concentration of the whitened coffee concentrate is above about 25% by weight.
 2. The concentrate of claim 1, wherein the concentrate shows substantially no change in viscosity after at least 5 months storage at room temperature.
 3. The concentrate of claim 1, wherein the ratio, on a dry basis, of non-fat milk solids to coffee solids is between about 1:0.1 and 1:0.7.
 4. The concentrate of claim 1, wherein the coffee aroma is provided in the form of an aromatized coffee concentrate.
 5. The concentrate of claim 4, wherein the aromatized coffee concentrate has a total organic content (TOC) of above about 300 mg/100 g of aromatized coffee concentrate.
 6. The concentrate of claim 4 wherein the aromatized coffee concentrate has a total organic content (TOC) of above about 450 mg/100 g of aromatized coffee concentrate.
 7. The concentrate of claim 1, wherein the coffee aroma includes highly volatile aroma components.
 8. The concentrate of claim 1, wherein the concentrate comprises between about 50% and 60% sugar, between about 15% and 25% non fat milk solids, between about 8% and 15% soluble coffee solids, and between about 8% and 15% milk fat, the percentages being on the basis of dry weight.
 9. The concentrate of claim 1, wherein the solids concentration is between about 70% and 80% by weight.
 10. The concentrate of claim 1, further comprising one or more additives selected from the group consisting of buffers, sweeteners, flavorings, colorings, emulsifiers, and mixtures thereof.
 11. The concentrate of claim 1, wherein the concentrated soluble coffee solids are enzymatically hydrolyzed.
 12. The stable, whitened coffer concentrate of claim 4, wherein the aromatized coffee concentrate has a total organic content (TOC) of at least about 350 to 450 mg/100 g of aromatized coffee concentrate.
 13. The stable, whitened coffee concentrate of claim 1, wherein the sufficient amount is about 1 to 3 weight percent of the total whitened coffee concentrate.
 14. The stable, whitened coffee concentrate of claim 1, wherein the whitened coffee concentrate can be stored for at least 5 months without flavor-degradation and harsh acidity.
 15. The stable, whitened coffee concentrate of claim 1, wherein the whitened coffee concentrate exhibits reduced gelation and sedimentation compared to a concentrate that does not have a sufficient amount of coffee aroma to stabilize the whitened coffee concentrate. 